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338 lines
12 KiB
Java
338 lines
12 KiB
Java
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* Copyright by The HDF Group. *
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* Copyright by the Board of Trustees of the University of Illinois. *
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* All rights reserved. *
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* *
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* This file is part of HDF5. The full HDF5 copyright notice, including *
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* terms governing use, modification, and redistribution, is contained in *
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* the files COPYING and Copyright.html. COPYING can be found at the root *
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* of the source code distribution tree; Copyright.html can be found at the *
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* root level of an installed copy of the electronic HDF5 document set and *
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* is linked from the top-level documents page. It can also be found at *
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* http://hdfgroup.org/HDF5/doc/Copyright.html. If you do not have *
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* access to either file, you may request a copy from help@hdfgroup.org. *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/************************************************************
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This example shows how to read and write data to a dataset
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using szip compression. The program first checks if
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szip compression is available, then if it is it writes
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integers to a dataset using szip, then closes the file.
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Next, it reopens the file, reads back the data, and
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outputs the type of compression and the maximum value in
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the dataset to the screen.
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************************************************************/
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package examples.datasets;
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import java.util.EnumSet;
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import java.util.HashMap;
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import java.util.Map;
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import hdf.hdf5lib.H5;
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import hdf.hdf5lib.HDF5Constants;
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public class H5Ex_D_Szip {
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private static String FILENAME = "H5Ex_D_Szip.h5";
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private static String DATASETNAME = "DS1";
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private static final int DIM_X = 32;
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private static final int DIM_Y = 64;
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private static final int CHUNK_X = 4;
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private static final int CHUNK_Y = 8;
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private static final int RANK = 2;
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private static final int NDIMS = 2;
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// Values for the status of space allocation
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enum H5Z_filter {
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H5Z_FILTER_ERROR(HDF5Constants.H5Z_FILTER_ERROR), H5Z_FILTER_NONE(HDF5Constants.H5Z_FILTER_NONE), H5Z_FILTER_DEFLATE(
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HDF5Constants.H5Z_FILTER_DEFLATE), H5Z_FILTER_SHUFFLE(HDF5Constants.H5Z_FILTER_SHUFFLE), H5Z_FILTER_FLETCHER32(
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HDF5Constants.H5Z_FILTER_FLETCHER32), H5Z_FILTER_SZIP(HDF5Constants.H5Z_FILTER_SZIP), H5Z_FILTER_NBIT(
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HDF5Constants.H5Z_FILTER_NBIT), H5Z_FILTER_SCALEOFFSET(HDF5Constants.H5Z_FILTER_SCALEOFFSET), H5Z_FILTER_RESERVED(
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HDF5Constants.H5Z_FILTER_RESERVED), H5Z_FILTER_MAX(HDF5Constants.H5Z_FILTER_MAX);
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private static final Map<Integer, H5Z_filter> lookup = new HashMap<Integer, H5Z_filter>();
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static {
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for (H5Z_filter s : EnumSet.allOf(H5Z_filter.class))
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lookup.put(s.getCode(), s);
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}
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private int code;
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H5Z_filter(int layout_type) {
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this.code = layout_type;
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}
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public int getCode() {
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return this.code;
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}
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public static H5Z_filter get(int code) {
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return lookup.get(code);
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}
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}
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private static boolean checkSzipFilter() {
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try {
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int available = H5.H5Zfilter_avail(HDF5Constants.H5Z_FILTER_SZIP);
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if (available == 0) {
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System.out.println("szip filter not available.");
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return false;
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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try {
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int filter_info = H5.H5Zget_filter_info(HDF5Constants.H5Z_FILTER_SZIP);
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if (((filter_info & HDF5Constants.H5Z_FILTER_CONFIG_ENCODE_ENABLED) == 0)
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|| ((filter_info & HDF5Constants.H5Z_FILTER_CONFIG_DECODE_ENABLED) == 0)) {
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System.out.println("szip filter not available for encoding and decoding.");
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return false;
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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return true;
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}
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private static void writeSzip() {
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long file_id = -1;
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long filespace_id = -1;
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long dataset_id = -1;
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long dcpl_id = -1;
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long[] dims = { DIM_X, DIM_Y };
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long[] chunk_dims = { CHUNK_X, CHUNK_Y };
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int[][] dset_data = new int[DIM_X][DIM_Y];
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// Initialize data.
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for (int indx = 0; indx < DIM_X; indx++)
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for (int jndx = 0; jndx < DIM_Y; jndx++)
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dset_data[indx][jndx] = indx * jndx - jndx;
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// Create a new file using default properties.
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try {
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file_id = H5.H5Fcreate(FILENAME, HDF5Constants.H5F_ACC_TRUNC, HDF5Constants.H5P_DEFAULT,
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HDF5Constants.H5P_DEFAULT);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Create dataspace. Setting maximum size to NULL sets the maximum
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// size to be the current size.
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try {
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filespace_id = H5.H5Screate_simple(RANK, dims, null);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Create the dataset creation property list, add the szip compression
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// filter.
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try {
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dcpl_id = H5.H5Pcreate(HDF5Constants.H5P_DATASET_CREATE);
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if (dcpl_id >= 0) {
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H5.H5Pset_szip(dcpl_id, HDF5Constants.H5_SZIP_NN_OPTION_MASK, 8);
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// Set the chunk size.
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H5.H5Pset_chunk(dcpl_id, NDIMS, chunk_dims);
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Create the dataset.
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try {
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if ((file_id >= 0) && (filespace_id >= 0) && (dcpl_id >= 0))
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dataset_id = H5.H5Dcreate(file_id, DATASETNAME, HDF5Constants.H5T_STD_I32LE, filespace_id,
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HDF5Constants.H5P_DEFAULT, dcpl_id, HDF5Constants.H5P_DEFAULT);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Write the data to the dataset.
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try {
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if (dataset_id >= 0)
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H5.H5Dwrite(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, HDF5Constants.H5S_ALL,
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HDF5Constants.H5P_DEFAULT, dset_data);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// End access to the dataset and release resources used by it.
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try {
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if (dcpl_id >= 0)
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H5.H5Pclose(dcpl_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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try {
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if (dataset_id >= 0)
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H5.H5Dclose(dataset_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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try {
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if (filespace_id >= 0)
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H5.H5Sclose(filespace_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Close the file.
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try {
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if (file_id >= 0)
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H5.H5Fclose(file_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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}
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private static void readSzip() {
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long file_id = -1;
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long dataset_id = -1;
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long dcpl_id = -1;
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int[][] dset_data = new int[DIM_X][DIM_Y];
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// Open an existing file.
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try {
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file_id = H5.H5Fopen(FILENAME, HDF5Constants.H5F_ACC_RDONLY, HDF5Constants.H5P_DEFAULT);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Open an existing dataset.
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try {
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if (file_id >= 0)
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dataset_id = H5.H5Dopen(file_id, DATASETNAME, HDF5Constants.H5P_DEFAULT);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Retrieve the dataset creation property list.
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try {
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if (dataset_id >= 0)
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dcpl_id = H5.H5Dget_create_plist(dataset_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Retrieve and print the filter type. Here we only retrieve the
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// first filter because we know that we only added one filter.
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try {
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if (dcpl_id >= 0) {
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// Java lib requires a valid filter_name object and cd_values
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int[] flags = { 0 };
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long[] cd_nelmts = { 1 };
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int[] cd_values = { 0 };
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String[] filter_name = { "" };
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int[] filter_config = { 0 };
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int filter_type = -1;
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filter_type = H5
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.H5Pget_filter(dcpl_id, 0, flags, cd_nelmts, cd_values, 120, filter_name, filter_config);
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System.out.print("Filter type is: ");
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switch (H5Z_filter.get(filter_type)) {
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case H5Z_FILTER_DEFLATE:
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System.out.println("H5Z_FILTER_DEFLATE");
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break;
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case H5Z_FILTER_SHUFFLE:
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System.out.println("H5Z_FILTER_SHUFFLE");
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break;
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case H5Z_FILTER_FLETCHER32:
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System.out.println("H5Z_FILTER_FLETCHER32");
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break;
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case H5Z_FILTER_SZIP:
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System.out.println("H5Z_FILTER_SZIP");
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break;
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case H5Z_FILTER_NBIT:
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System.out.println("H5Z_FILTER_NBIT");
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break;
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case H5Z_FILTER_SCALEOFFSET:
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System.out.println("H5Z_FILTER_SCALEOFFSET");
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break;
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default:
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System.out.println("H5Z_FILTER_ERROR");
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}
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System.out.println();
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Read the data using the default properties.
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try {
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if (dataset_id >= 0) {
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H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, HDF5Constants.H5S_ALL,
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HDF5Constants.H5P_DEFAULT, dset_data);
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}
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Find the maximum value in the dataset, to verify that it was read
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// correctly.
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int max = dset_data[0][0];
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for (int indx = 0; indx < DIM_X; indx++) {
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for (int jndx = 0; jndx < DIM_Y; jndx++)
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if (max < dset_data[indx][jndx])
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max = dset_data[indx][jndx];
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}
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// Print the maximum value.
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System.out.println("Maximum value in " + DATASETNAME + " is: " + max);
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// End access to the dataset and release resources used by it.
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try {
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if (dcpl_id >= 0)
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H5.H5Pclose(dcpl_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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try {
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if (dataset_id >= 0)
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H5.H5Dclose(dataset_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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// Close the file.
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try {
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if (file_id >= 0)
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H5.H5Fclose(file_id);
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}
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catch (Exception e) {
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e.printStackTrace();
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}
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}
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public static void main(String[] args) {
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// Check if gzip compression is available and can be used for both
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// compression and decompression. Normally we do not perform error
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// checking in these examples for the sake of clarity, but in this
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// case we will make an exception because this filter is an
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// optional part of the hdf5 library.
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if (H5Ex_D_Szip.checkSzipFilter()) {
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H5Ex_D_Szip.writeSzip();
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H5Ex_D_Szip.readSzip();
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}
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}
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}
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